Preheat the oven to 350°F (175°C) and grease a 9-inch round or square cake pan.
In a bowl, whisk flour, baking powder, baking soda, salt, and espresso powder.
In another bowl, beat butter and sugar until creamy. Add eggs and vanilla, mixing until smooth.
Stir in sour cream. Gradually add dry ingredients, mixing until just combined.
For the almond streusel, mix sliced almonds, brown sugar, flour, butter, and cinnamon.
Pour half of the batter into the pan. Sprinkle with almond streusel.
Top with the remaining batter and sprinkle with more streusel.
Bake for 35-40 minutes or until a toothpick inserted comes out clean.
Let the cake cool on a rack before serving.